Due to the effects of global warming, the ice in polar regions is thawing at a fast rate, and accordingly, the amount of ice sheets and glaciers is decreasing. The melting of glaciers is especially serious over Arctic Ocean in summer, and this is posing a threat to the entire global climate system.
The average albedo of the Earth overall (the percentage of solar energy reflected at the surface) is 31%. The albedo of ice sheets and glaciers, etc., is about 70 to 90%, and the albedo of the oceans is about 8 to 9%. Therefore, as a rise in the Earth's temperature causes the ice sheets and glaciers to melt, the average albedo of the Earth may be decreased accordingly. The seawater, having absorbed more solar energy, may become warmer and may thus accelerate the melting of the glaciers.
At present, all of the first-year ice (ice having a thickness of about 1 m or lower) at the North Pole is thawed in the summer of the same year. In addition, much of the multi-year ice (ice having a thickness of about 1 to 3 m) is also thawed every year. At this rate, it is estimated that all of the ice at the North Pole will disappear by the year 2050. In particular, the rate of melting is observed to be much faster than at first predicted, indicating the seriousness of the problem.
Although it is impossible to know what disasters will be incurred if all of the ice over the Arctic Oceans is melted, it is certain that there will be dire consequences. However, the efforts of the human race in responding to this problem are focused only on reducing carbon emissions, and there are no actions under way for protecting ice sheets and glaciers or for delaying the rate of melting.
Due to its salinity, seawater is not easily frozen. If the salinity is 24.695%, the seawater reaches its maximum density, and at the same time reaches its freezing point, at −1.33° C. If the oceans are assumed to have an average salinity of 35%, the freezing point is known to be −1.8° C., and the temperature at maximum density is known to be −3.5° C.
The temperature at the water level of the Arctic Ocean rarely descends below −1° C., even in the winter. Moreover, the cold seawater cooled by the winter air is increased in density and is thus moved to the bottom of the sea, while the relatively warm seawater from the bottom is moved upward. This phenomenon of convection makes it even more difficult for seawater to form ice.
Much of the ice that covers the North Pole in winter is produced by freshwater flowing in from the continents (from Russia, etc., for example) and freezing before it mixes with seawater, or by snow, etc., forming a layer of ice on the water surface and accumulating on the ice layer. Therefore, ice may be formed earlier in regions of the sea that are close to the continent, compared to regions of the sea that are far from the shore. That is, unless the temperature is very low, or there is a heavy downfall of snow, etc., so that a layer of ice is formed, the snow falling on the sea is absorbed into the sea, and the ice forming on the waters of the offshore sea cannot reach a considerable thickness.
The average temperature at the water level of the Arctic Ocean actually drops below zero degrees in November, and the sub-zero temperature continues into May. The period when the ice is the thickest is in March. However, even when both the water temperature and the air temperature are below zero, there are still regions and periods in which no ice is formed. If a small area of ice were to be formed artificially in such a region, it may be possible to form a layer of ice at an earlier period than under natural circumstances. Then, the period during which the ice layer is formed can be extended, so that a broader and thicker layer of ice may be obtained than under natural circumstances.
This broader and thicker layer of ice may continuously reflect solar energy until its thawing. Moreover, when it is finally thawed in the summer season, the thawing may reduce the temperatures of the surrounding water and air, to delay the melting of nearby ice sheets and glaciers. Until now, there has not been an attempt to artificially form and increase the thickness of a layer of ice in an offshore sea. Of course, a patent on “A METHOD OF ICE KEEPING IN RESERVOIR (Korean registered patent no. 10-829825)” has been filed by the applicant, but the patent relates to a method of producing ice from freshwater and therefore may not easily be applied to seawater.